This invention relates in general to a coded lock device and in particular to a coded-card type lock device in which a calling-card type key and a digitalized locking unit are arranged to be locked and unlocked. The card-type key is selectively provided with numerical or alphabaetical codes while the locking unit has a plurality of digitalized locking pieces which are mechanically designed on a binary basis and reversibly disposed in the locking unit in cooperation with the card-type key so that the codes of both the card-type key and the locking pieces can be simultaneously set at any time for ensuring its highly protective capability
At present, the conventional door locks have the following disadvantages:
(1) As the known door lock such as the snap type is usually combined with pin tumblers and spring for locking and unlocking, it is easy for any unauthorized person to unlock it with a probe.
(2) If the key is lost or not carried along, it has to be unlocked by a locksmith, incurring a lot of inconvenience.
(3) On the occasions where the key is lost or often transferred from person to person such as for a rent room or a hotel room, more duplications of the same key have to be made, always posing a safety problem.
(4) Traditional keys are usually made with different serrations, slots and wards. When they are strung together, it is not only heavy and inconvenient to use and carry, but also bulky and noisy when carried in one's pocket.
(5) Electronic or magnetic door locks produced for surmounting the aforesaid disadvantages are expensive and, moreover, are not as sturdy and taugh as mechanical door locks.